Method of bending a metal sheet and a corner produced thereby

ABSTRACT

A method for bending a metal sheet along a selected line to provide a smooth bending edge. The metal sheet is indented along the selected line to produce a groove in one face and a bead in the opposite face. The metal sheet is then shaped into sections having a common bending edge coincident with the selected line and such that the inside of the bending edge is formed by the bead and the outside of the bending edge is formed by the groove.

United States Patent [191 Tischuk May 6,1975

[ METHOD OF BENDING A METAL SHEET AND A CORNER PRODUCED THEREBY [75] Inventor: Walter Tischuk, Richmond, Ind.

[73] Assignee: H. H. Robertson Company,

Pittsburgh, Pa.

[22] Filed: Aug. 16, 1973 211 App1.No.:388,955 7 Related U.S. Application Data [62] Division of Ser. No. 149,245, June 2, 1971,

abandoned.

[52] U.S. Cl. 72/46; 29/DlG. 3; 2 9/DlG. 33; 29/5272 [51] Int. Cl..... B2ld 5/00; B2ld 11/20; B21d 21/00 [58] Field of Search 29/527.4,.DIG. 3, DIG. 33, 29/5272; 52/98, 595, 656, 667; 72/46 [56] v 9 References Cited UNITED STATES PATENTS 918,366 4/1909 Quereau 52/98' 944,536 12/1909 Bonfield et al. 29/DlG. 33

1,992,835 2/1935 Newman 72/379 2,728,479 12/1955 Wheeler 52/98 X 3,175,655 3/1965 Brown et al. 52/98 X 3,376,670 4/1968 Jones 52/656 X 3,465,424 9/1969 Deringer.... 29/5272 3,478,483 11/1969 Baker 52/98 3,667,180 6/1972 Tischuk 52/595 X Primary Examiner-C. W. Lanham Assistant Examiner-E. M. Combs Attorney, Agent, or Firm-l-larry B. Keck; George E. Manias I [5 7] ABSTRACT A method for bending a metal sheet along a selected line to provide a smooth bending edge. The metal sheet is indented along the selected line to produce a groove in one face and a bead in the opposite face.

The metal sheet is then shaped into sections having a common bending edge coincident with the selected line and such that the inside of the bending edge is formed by the bead and the outside of the bending edge is formed by the groove.

8 Claims, 10 Drawing Figures PATENTEDHAY 8I975 3.881.338

SHEET 1!]? 2 PATEIEBW W5 SHEET 2 OF 2 METHOD OF BENDING A METAL SHEET AND A CORNER PRODUCED THEREBY CROSS-REFERENCES TO RELATED APPLICATIONS This application is a diversion of copending application Ser. No. 149,245 filed Jun. 2, 1971, now abandoned, and assigned to the assignee of this invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method of bending a metal sheet and to corners produced thereby.

2. Description of the Prior Art Numerous methods for bending a metal sheet along a selected line are known in the art. Metal sheets have been bent by hand over mandrils or by power actuated break forming apparatus.

It is also known to cold-work strain-harden a metal sheet by imparting to the metal sheet-a ridge-andgroove or undulatory profile. In addition to increasing the strength of the metal sheet, an added advantage is that the sheet may be sent into sections having a common bending edge such that the outside of the edge is formed by a ridge and the inside of the bending edge is formed by a complementing groove. See U.S. Pat. No. 3,165,815 (A. WOGERBAUER, Jan. I9, 1965). Metal sheets having an undulatory profile are not architecturally acceptable for use as facing sheets in wall constructions.

Wall panels formed from a pair of facing sheets and an intermediate core are used extensively in the construction of various types of enclosures. A prevalent trend in present day panel design is the bending of the panels to produce corner constructions of desired architectural appearance. Numerous methods have been proposed for bending such panels. See, for example U.S. Pat. Nos. issued to G. G. Meyercord, Nos. 1,440,615 (Jan. 2, 1923); 1,549,205 (Au'g. II, 1925); l,67l,084 (May 22, 1928); and the U.S. Pat. Issued to M. E. Nerem, No. 3,496,689 (Feb. 24, I970). Basically, these methods consist of notching the panel to remove a segment of the inner facing sheet and the core and this provide a V-shaped groove having an apex adjacent to the exterior facing sheet. The exterior facing sheet is then bent along the base of the groove to move the exposed core surfaces and inner facing sheet edges into juxtaposition. At the bend line, the exterior facing sheet undergoes a stretch bend. Where the exterior facing sheet has a brittle decorative coating, flaws, such as rust initiating fissures and spalling of the decorative coating, may result from the bending.

SUMMARY OF THE INVENTION The principal object of this invention is to provide a method for bending a metal sheet, such as a wall panel, along a selected line and an improved corner configuration produced thereby.

Another object of this invention is to provide a method for bending a metal sheet having a brittle decorative coating on its exposed face without producing rust initiating fissures and other flaws in the decorative coating at the bending edge.

A still further object of this invention is to provide a method for bending a laminated building panel by which the building panel is shipped to the job site in a flat condition and is bent at the job site.

A further object of this invention is to provide a method by which single metal sheets and laminated building panels may be bent by hand along one or more selected lines to produce inside and outside corner structures.

In accordance with the present invention, a metal sheet is indented along a selected line to produce a groove in one face of the metal sheet and a bead in the opposite face of the metal sheet. The metal sheet is bent into angularly presented sheet portions having a common bending edge coincident with the selected line. The bending of the metal sheet is such that the inside of the common bending edge is formed by the bead and the outside of the common bending edge is formed by the groove. The groove presented by the metal sheet prior to bending is not visually discernible after bendmg.

Further in accordance with the present method, a brittle decorative coating, such as a vitreous enamel coating, may be applied to that face of the metal sheet presenting the groove. Thereafter, the metal sheet is bent. In the resultant bending edge the protective coating is essentially free of fissures and other flaws.

The present method may be employed to bend panels of a variety of different constructions. Such panels include the two component type formed from a facing sheet and a backing member. The backing member may comprise a self-adheringfoamed-in-place plastic composition or a preformed block of foamed plastic composition secured to the facing sheet by a film of adhesive. Such panels also include the three component type formed from a pair of facing sheets having a core material therebetween. The core material may comprise a self-adhering foamed-in-place plastic core or a preformed block of foamed plastic composition secured to the facing sheets by films of adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4, inclusive, are isometric views of a fragment of a metal sheet, illustrating the method of the present invention;

FIG. 5 is a fragmentary side view of a facing sheet provided with an indentation and notches according to the present invention; 7

FIG. 6 is a broken, cross-sectional, isometric view of a foam core building panel incorporating the facing sheet of FIG. 5;

FIG. 7 is a fragmentary side view of the panel of FIG. 6 illustrating notching of the panel prior to bending;

FIG. 8 is a fragmentary side view of the panel of FIG. 6 after bending;

- FIG. 9 is a cross-section taken longitudinally through a foam core panel illustrating notching and cutting of thepanel prior to bending; and

FIG. 10 is a longitudinal section, similar to FIG. 9, illustrating the panel of FIG. 9 after bending.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S) FIGS. 1 to 4 illustrate the steps in bending a metal sheet 15 about a selected line represented by the dash dot line 16. The metal sheet 15 may have a thickness in the range of 16 to 30 gauge. The metal sheet 15 may comprise materials, such as steel, metal coated steel, stainless steel, weathering steel, aluminized steel, aluminum and the like.

In accordance with the present invention, the metal sheet is indented (FIG. 2) along the selected line 16 to produce a groove 17 in one face 18 of the metal sheet 15 and a complementing bead 19 in the opposite face 20 of the metal sheet 15. Thereafter, the indented metal sheet 15 is bent about the selected line 16 (FIG. 4) to provide angularly presented sheet portions 21, 22 having a common bending edge 23. The indented metal sheet is bent such that the inside are 24 of the common bending edge 23 is formed by the bead 19 (FIG. 2) and the outside are 25 of the bending edge 23 is formed by the groove 17 (FIG. 2). The arrangement is such that the originally presented groove 17 (FIG. 2) is not visually discernible as a concavity after the metal sheet 15 has been bent (FIG. 3).

It will be observed in FIG. 2 that the surface of the groove 17 consists of a central concave arc segment 26 and convex arc segments 27, each providing a smooth transition between one edge of the concave arc segment 26 and the face 18 of the metal sheet 15. The convex arc segments 27 preferably are formed with a radius R, which is substantially equal to-the radius R; (FIG. 3) of the common bending edge 23.

It will also be observed in FIG. 2 that the groove 17 has a girth indicated by the dimension line labelled G which is the sum of the peripheral lengths of the two convex arc segments 27 and the concave arc segment 26. The common bending edge 23 (FIG. 3) has a girth indicated by the dimension line labelled G In accordance with the present invention, the girth G, of the groove 17 is undisturbed during bending of the metal sheet l 5 and is substantially equal to the girth G of the common bending edge 23 (FIG. 3).

Referring to FIG. 4, the face 18 of the metal sheet 15 may receive a brittle decorative coating 28, such as a vitreous enamel coating. In accordance with the present invention, the coating 28 is applied to the face 18 after indenting the metal sheet 15 (FIG. 2) but prior to bending the metal sheet 15 (FIG. 3). Since the girth G, of the groove 17 remains undisturbed during bending of the metal sheet 15, after bending, the decorative coating 28 is substantially free of rust initiating fissures, spalling and similar flaws.

In FIG. 3, the sheet portions 21, 23 are mutually perpendicular. It should be evident, however, that the present method may be employed to produce bends wherein the included angle between the contiguous sheet portions is acute or obtuse.

The present method may be employed to bend building panels, such as the foam core panel 29 of FIG. 6. The panel 29 may comprise that panel described and illustrated in copending application Ser. No. 86,425, filed Nov. 3, 1970 and assigned to the assignee of this invention. For a complete description of the panel 29 reference is directed to the aforesaid copending application Ser. No. 86,425. However, for the purposes of the present invention it is believed sufficient to state that the panel 29 comprises an outer facing sheet 30, an inner facing sheet 31 and a foam core 32 filling the space between the facing sheets 30, 31. The outer facing sheet includes a central pan 33 having side walls 34, 35 provided along its opposite longitudinal edges. The side walls 34, 35 are provided with complementary mating elements 36, 37.

In accordance with the present invention, the central web 33 of the outer facing sheet 30 (FIG. 5) is transversely indented to produce a groove 17 in the exposed face 38 and a complementing bead 19 in the hidden face 39. The side walls 34, 35 may be notched as at 39, 40 respectively.

The indentation and notching of the outer facing sheet 30 are performed prior to the assembly of the panel 29. After the facing sheet 30 has been assembled in the panel 29 (FIG. 6) the indentation (groove 17) is clearly visible in the exposed face 38. The foam core 32 also is visible at the notch 40 in the side wall 35 and at the notch 39 (not visible) in the side wall 34. The indentation (groove 17) indicates to the worker the exact location of the desired corner. After the panel 29 reaches the job site, saw cuts are made along the lines indicated at 42 (FIG. 7) to remove the triangularshaped panel segment 43. Thereafter, the panel 29 is bent by hand to produce the corner structure 44 illustrated in FIG. 8.

FIGS. 9 and 10 illustrate the manner of forming multiple bends in a single panel identified generally by the numeral 45. The panel 45 includes outer and inner facin g sheets 46, 47 and a foam core 48. The panel 45 may be similar to the panel 29 of FIG. 6.

Referring to FIG. 9, the outer facing sheet 46 prior to being assembled into the panel 45 is transversely indented at selected spaced locations to produce the exposed grooves 17a, 17b and the corresponding complementing beads 19a, 19b. The facing sheet 46 is assembled with the facing sheet 47 and the foam core to produce the panel 45. The panel 45 is shipped in the flat condition to the job site. At the job site, a first cut represented by the dash line 57 is made through the inner facing sheet 47 and the foam core 48. The first cut 57 terminates adjacent to the complementing bead 19a. The first cut 57 divides the panel 45 into two contiguous panel segments identified by-the numerals 45a, 45b. Second and third cuts represented by the dash lines 49, 50, respectively are made through the inner sheet 47 and the foam core 48 and terminate adjacent to the complementing bead 19b. After the cuts 49, 50 have been completed, the triangular-shaped segment 51 is removed. It will be observed that the cuts 49, 50 further divide the panel 45 into contiguous panel segments identified generally by the numerals 45b, 450.

The thus preparedlpanel 45 is bent to produce the inside corner 53 and the outside corner 54 illustrated in FIG. 10. To produce the inside corner 53, the facing sheet 46 is bent to provide the angularly present panel segments 45a, 45b which have a common bending edge 52. When forming the inside corner 53, the inside of the common bending edge 52 is formed by the groove 17a and the outside of the bending edge 52 is formed by the bead 190.

To produce the outside corner 54, the facing sheet 46 is bent in the direction of the arrow 56 (FIG. 9) whereby the panel segments 45b, 450 are angularly presented and have a common bending edge 23. The outside corner 54 is formed in accordance with the present invention. Thus. the inside of the common bending edge 23 is formed by the complementing bead 19b (FIG. 9) and the outside of the common bending edge 23 is formed by the groove 17b (FIG. 9). The groove 17b which is visible in the unberit panel 45 of FIG. 9 is not visually discernible as a concavity in the outside corner 54 of FIG. 10.

I claim:

1. A method of bending a building panel along a se-,

lected line, comprising providing a metal facing sheet having an exposed face and a hidden face;

indenting said facing sheet along said selected line to produce a groove in said exposed face and a complementing bead in said hidden face;

applying a backing to substantially the entire area of said hidden face;

notching said backing to provide a V-groove having an apex proximate to and parallel with said complementing bead; and

bending said building panel about said selected line to provide angularly presented panel segments having a common bending edge and such that the inside of said common bending edge is formed from said complementing bead and the outside of said common bending edge is formed from said groove.

2. The method of claim 1 including the step of applying a brittle decorative coating to said exposed face of said facing sheet after indenting but prior to bending said building panel.

3. The method of claim 1 wherein said backing comprises a foamed plastics composition.

4. The method of claim 1 wherein said backing comprises a slab of foamed plastics composition having one face secured to said hidden face of said facing sheet and an opposite face; and

an inner skin substantially coextensive with said opposite face of said block of foam plastics composition.

5. A method of bending a laminated building panel along a first selected line to provide an outside corner and along a second selected line spaced from said first selected line to provide an inside corner, comprising providing a metal facing sheet having an exposed face and a hidden face;

indenting said facing sheet along each said line to produce a groove in said exposed face and a complementing bead in said hidden face.

applying a backing over substantially the entire area of said hidden face;

notching said backing to provide a V-groove having an apex proximate to and parallel with the complementary bead of said first selected line;

cutting through said backing in a direction parallel with said second selected line to the complementing bead of said second selected line;

bending said building panel about said first selected line to provide angularly presented panel segments having a common bending edge and such that the inside of said common bending edge is formed from said complementing bead and the outside of said common bending edge is formed from said groove; and

bending said building panel about said second selected line to provide angularly presented panel segments having a common bending edge and such that the inside of said common bending edge is formed from said groove and the outside of said common bending edge is formed from said complementing bead.

6. The method of claim 1 wherein prior to bending said building panel, the surface of said groove in said facing sheet consists of a concave arc segment having opposite edges; and

convex arc segments, each providing a smooth transition between one of said edges of said concave arc segment and said exposed face of said facing sheet.

7. The method of claim 6 wherein each of said convex arc segments is formed with a radius equal to the radius of said common bending edge.

8. The method of claim 1 wherein the girth of said groove is substantially equal to the girth of said common bending edge. 

1. A method of bending a building panel along a selected line, comprising providing a metal facing sheet having an exposed face and a hidden face; indenting said facing sheet along said selected line to produce a groove in said exposed face and a complementing bead in said hidden face; applying a backing to substantially the entire area of said hidden face; notching said backing to provide a V-groove having an apex proximate to and parallel with said complementing bead; and bending said building panel about said selected line to provide angularly presented panel segments having a common bending edge and such that the inside of said common bending edge is formed from said complementing bead and the outside of said common bending edge is formed from said groove.
 2. The method of claim 1 including the step of applying a brittle decorative coating to said exposed face of said facing sheet after indenting but prior to bending said building panel.
 3. The method of claim 1 wherein said backing comprises a foamed plastics composition.
 4. The method of claim 1 wherein said backing comprises a slab of foamed plastics composition having one face secured to said hidden face of said facing sheet and an opposite face; and an inner skin substantially coextensive with said opposite face of said block of foam plastics composition.
 5. A method of bEnding a laminated building panel along a first selected line to provide an outside corner and along a second selected line spaced from said first selected line to provide an inside corner, comprising providing a metal facing sheet having an exposed face and a hidden face; indenting said facing sheet along each said line to produce a groove in said exposed face and a complementing bead in said hidden face. applying a backing over substantially the entire area of said hidden face; notching said backing to provide a V-groove having an apex proximate to and parallel with the complementary bead of said first selected line; cutting through said backing in a direction parallel with said second selected line to the complementing bead of said second selected line; bending said building panel about said first selected line to provide angularly presented panel segments having a common bending edge and such that the inside of said common bending edge is formed from said complementing bead and the outside of said common bending edge is formed from said groove; and bending said building panel about said second selected line to provide angularly presented panel segments having a common bending edge and such that the inside of said common bending edge is formed from said groove and the outside of said common bending edge is formed from said complementing bead.
 6. The method of claim 1 wherein prior to bending said building panel, the surface of said groove in said facing sheet consists of a concave arc segment having opposite edges; and convex arc segments, each providing a smooth transition between one of said edges of said concave arc segment and said exposed face of said facing sheet.
 7. The method of claim 6 wherein each of said convex arc segments is formed with a radius equal to the radius of said common bending edge.
 8. The method of claim 1 wherein the girth of said groove is substantially equal to the girth of said common bending edge. 